[1][2] Eekaulostomus was a syngnathiform, a member of the same order as modern trumpetfish, cornetfish, pipefish, and seahorses.

Its exact phylogenetic placement among the sygnanthiforms is debated, although it is known to belong to the "long-snouted" group (Syngnathoidei); it was initially recovered as allied with the trumpetfish superfamily (Aulostomoidea), but more recent studies have found it to be more closely related to the pipefish superfamily (Syngnathoidea).

[2][3][4] The only known specimen of Eekaulostomus was found in exposures of the Tenejapa-Lacandón Unit in the Belisario Domínguez quarry near the ancient Mayan city of Palenque.

It inhabited the Caribbean region in the Early Paleocene, just a few million years after the Cretaceous–Paleogene extinction event.

The relative proximity of the locality to the Chicxulub crater indicates that marine ecosystems had likely recovered rapidly after the event, and that syngnathiformes are an ancient clade.